Electronic apparatuses such as mobile phones, personal digital assistants, and personal computers have been developed. Such electronic apparatuses are equipped with a display device including a touch panel function as a form of user interface. These electronic apparatuses usually include a capacitive touch panel function. In a capacitive touch panel, conductive electrodes are disposed on the panel, and a contact position of a finger or a pen on the surface of the panel is sensed based on change in capacity between the electrode and the finger or the like.
An electronic apparatus having the above touch panel function is known as having a structure in which a touch panel board is separately bonded to a display device such as a liquid crystal display device and an organic EL display device, to add a touch panel function.
In the meantime, in electronic apparatuses using a liquid crystal device (LCD), an in-cell structure is being generalized. In the in-cell structure, a touch panel function is formed inside the LCD device. Adopting the in-cell structure produces the merit that the thickness and the weight of the devices are reduced, because it becomes unnecessary to use a dedicated touch panel.
On the other hand, in OLED display devices using organic light emitting diodes (OLED), it is difficult to provide a touch panel function inside in the same form as LCD devices, because a cathode provided on the whole light-emitting display surface thereof serves as an electromagnetic shield.